EP2314427B1 - Method and device for controlling electrical devices by means of motion detection - Google Patents

Description

The invention generally relates to the control of electrical devices due to three-dimensional motion detection of objects in a surveillance space. More particularly, it relates to a control device employable by use of a suitable distance information providing and spatially resolving motion detector, and a method of controlling external electrical devices using such a control device which employs a suitable distance information providing and spatially resolving motion detector.

It is known to detect by means of various motion detectors the presence of persons in a particular detection area of a room based on electromagnetic radiation or sound waves and to control based on the detection of a connected external electrical device. Here is generally the switching on of lighting or cameras are known, which are combined with a motion detector and activated when the detector detects an object in the interstitial space, commonly referred to as Event. But even more complex systems can be controlled by means of motion detection, eg collision-free control of robots in automated systems. The condition is that as a result of Motion detection an output signal is generated, which is used for the control of the connected device. Since this output signal is regular, possibly also via various transformations of an electrical nature, the external device to be controlled with it should be referred to generally below as an electrical device.

While in active motion detectors an artificial source generates electromagnetic or sound waves to detect the current situation in the detection area, passive motion detectors use the waves present in the detection area with or without the presence of a person.

The passive detectors include in particular infrared motion detectors, which operate in the far infrared range and use the heat radiation of a person present in the detection area. The change in heat radiation associated with the movement of a person induces an electrical signal in the sensor of the motion detector which, by suitable signal conditioning for use in a subsequent switching stage, often the actuator of a control circuit such as the switching and dimming of lighting in dependence on the surrounding brightness, is provided. In the US 6,236.33 B1 For detecting a vehicle key instead of heat radiation, the magnetic flux density is continuously measured, so that from the change on the presence of the vehicle key, which has a permanent magnet, closed and a signal can be generated.

The passive motion detectors also include the so-called Reichardt detector, which detects brightness changes in the environment. Here, motion sequences are resolved locally, ie the direction of a movement is detected by signals from several, at least two adjacent receivers delayed and linked to each other. Such a motion detector is referred to as an EMD (Elementary Motion Detector) sensor. By using many EMDs, a direction- and speed-specific signal can be obtained and, with a suitable EMD arrangement, an entire half-space can be detected within an EMD array. For example, in vehicle assistance systems, the speed, including the angular velocity, and the direction of movement of an object approaching a vehicle can thus be determined.

For active motion detectors, various signals are used, from the reflection of which on an object the presence of the object in the interstitial space or its movement as well as various other values are determined ( WO 2008/154736 ). Thus, motion detectors are known, which can determine the distance, speed and acceleration of an object by means of the Doppler principle using runtime measurements by means of ultrasound pulses emitted by the detector.

A three-dimensional object recognition, which also includes distance information on the object, is often done by means of a stereo camera or scanner systems, which are very complex and expensive. A distance information can already be obtained by a so-called lidar system, which comprises a pulsed operation radiator, regularly an infrared laser, a photodiode, eg avalanche diodes, as a receiver and an evaluation. From runtime measurements of the emitted radiation reflected by the object, the distance to the object is determined in the evaluation electronics. An integrated in a vehicle light lidar system is in the DE 10 2006 044 794 A1 described.

The transit time measurement is by means of pulse measurement method or by detection from the phase shift of modulated light. While the pulse measurement method evaluates transit time differences between light pulses which are reflected on an object or not, the evaluation of the phase shift is based on continuously emitted light and its change as a result of reflection at an object,

For three-dimensional detection, a plurality of transmitting or receiving devices spread in the interstitial space or a combination of both are used so that the desired object position can be determined when the channel is separated. In the DE 10 2005 006 921 A1 For example, to detect an object contour, an array of PIN photodiodes is described, which are arranged as radiation detectors in two or more spaced-apart strips on a support. About transit time measurements of the radiation emitted by a pulsed radiation source objects are three-dimensional imageable.

A short-range sensor used for blind spot detection or parking space measurement in driver assistance systems comprises, according to DE 10 2004 062 022 A1 on the other hand, a row of transmitting elements which can be controlled in pulsed fashion, a further transmitting element arranged offset and radiating downwards, and a receiving device for the common evaluation of radiation reflected by objects. Again, the detection of objects by means of transit time measurement takes place.

These detection systems operate continuously or after manual or automatic initialization by a parent or overall system, such that the integration of range or motion detectors into an operating system such as a driver assistance system in terms of operational readiness is unproblematic. If, on the other hand, the higher-level or overall system is deactivated, energy storage may be required in order to keep the detection system on standby. Since stand-by times can be very long, especially in the case of vehicles, standby times of the detection system considerably burden the vehicle battery. But also for the detection mode, the power consumption should be reduced due to the high number of consumers in the overall system and due to the demands for improved energy efficiency.

It is therefore an object of the invention to provide a method for controlling external electrical devices by means of three-dimensional motion detection, which are inexpensive to produce and both have a low power consumption in standby mode and during operation of the device. The method should also be applicable to different consumers in the overall system.

By means of the method described below, the total power consumption is reduced by going through different states in succession and depending on the previous process steps, which are characterized by increasing power consumption. By determining the various states based on the measurements to be performed therein and verifying the need for the next higher system state based on the currently measurable situation in the interstitial space, the total power consumption required for device control could be minimized. Nevertheless, the entire system with the start of the main cycle, which is the basis of the complete control method, in continuous readiness for the immediate control of the external electrical device.

In the first system state, a standby state or sleep mode, only single measurements are carried out, which have a minimum of energy consumption through single and short signals. On the one hand, these measurements serve to monitor the environment and to identify a fundamentally suitable event in order, if appropriate, to move on to the next operating state which initiates the control. On the other hand, they also serve to exclude events that are comparable to the relevant event and thus are fundamentally suitable, but nevertheless should not serve the purpose of control. This exclusion occurs through the establishment of conditions that the previously identified event must meet in order to continue to be verified as relevant.

The minimization of the energy expenditure while maintaining the readiness of the device for control by a staggered method with identification, verification and exclusion criteria is supported by the subdivision of the interstitial space into a pre-warning area and a detection area. Events detected in the alert area always lead only to a next identification or verification step. This is the readiness, but the possibility of excluding an event is even higher. On the other hand, if the event is already detected in the detection area, the steps until the triggering of the control are regularly already reduced, so that the exclusion criteria lose significance.

This basic procedure with staggered system state in conjunction with a staggering of the interstitial space into less relevant and more relevant areas is based on different types of distance measurements applicable. The prerequisite for the selection of the detection method is that the distance measurement allows the assignment of the event to the prewarning area and to the detection area. An exact determination of the distance of the event to the sensor is possible, but not required.

Accordingly, in one embodiment of the method for the distance measurements to be carried out, the pulse measuring method is used. The following description is intended to be by way of example, but not by way of limitation, by this process.

Both aspects, identification and verification, are accomplished by comparable range measurements in which only the presence or absence of reflection of a transmitted light pulse, i. one of the entire monitoring space detecting optical pings, is determined within a matched to the extent of the interstitial space measurement window. This reduces the effort in terms of time and technology both for the measurement and for the evaluation. The control device is to a certain extent still in a sleep mode, but already identifies and verifies.

Even if the identification can take place both in the prewarning and in the detection area, a positive verification is linked to the detection area. In order to arrive at a clear verification as positive or negative for the verification measurement with only one measurement loop, according to a further embodiment of the method, the time t ₂ at which the verification measurement should take place is calculated for a positive verification measurement. For this purpose, a time difference Δ (t ₂ -t ₁ ) is determined, within which the event is located with high certainty in the detection area.

This calculation is based on the time t ₁ , at which a positive identification was made, an average speed of the event and the possible range of motion in the interstitial space. The possible range of motion includes the position of the event at time t ₁ both in the prewarning area and in the detection area.

Only when both identification and verification are positive, the next higher system state, the operating state is activated and a measurement cycle is started. This includes more extensive measurements to determine the position in the detection area and therefore has a higher energy consumption. However, due to the prerequisites to be fulfilled, this operating state is activated only in obviously relevant situations, so that the requirement for minimizing the power consumption for the entire control method can be met. Also for this step fundamentally different measuring methods are suitable.

Energy and technical complexity can be reduced according to an embodiment of the method, although these measurements are used to determine the position of the event in the area of the interstitial space, in which controls are triggered and this movements should be clearly localized and temporally identifiable by means of pulse measurement method and consequently the evaluation takes place at the pulses reflected at the event. Only if, regardless of the measuring method used, the position measurement also meets the predefined conditions, the control of the external electrical device takes place. This additional exclusion method, which is also limited to the detection range, serves both to protect against and save energy due to unintentional Triggering the generation of the output signal.

The actual control of the external electrical device, i. an electrical device outside the control device, by means of an analog and evaluable output signal which is generated in the control device and transmitted to the device. Thus, one pass of a control process is completed, so that the main cycle can be ended and the control device can be put into a sleep state. In this no further measurements are made.

The generation of the output signal takes place only after complete completion of the preceding measurement method, so that it is possible according to an embodiment of the method for further reduction of energy consumption, the function block of the control device, which serves the distance measurement and should be referred to as a distance block, before generation to disable the output signal.

If, as stated above, the pulse measuring method is used in one embodiment of the control method, a position determination is already possible in a simple manner by comparing the parameters of the reflected pulses with predetermined measured value ranges. For even the position determination is required only with such accuracy, which is predetermined by the size of the detection area.

Since a comparison with stored measured values is to take place for a plurality of the method steps described, a compensation of the fluctuations in the ambient brightness is advantageous on the basis of their determination as an optical base load. The minimization of the technical effort is also the measurement of the ambient brightness by means of pulse measurement method. This makes it possible to use the components of the control device that are used for the actual measurements, also for this measurement.

A further embodiment of the control method makes it possible to link the generation of the output signal per se or with regard to its type to a conscious action of the event. This is done via a spatially and temporally selected detection of a movement sequence of the event located in the detection area, which is effected by means of a function block for spatially and temporally selected detection of movement sequences in the detection area, hereinafter referred to as motion block.

Only the evaluation of the detected motion sequence leads to the decision on the output signal. Thus, a further exclusion criterion can be implemented before the generation of the output signal or different output signals can be generated with a method and a device. These can control an external electrical device differently or several devices separately.

In principle, different detection methods can also be used for this movement detection. The use of the device used for the distance measurement, possibly with a change of the configuration and / or with adapted light emitters, is possible if, in one embodiment of the method, the spatially and temporally selecting detection of motion sequences by sensing the change in the brightness values of an array of photodiodes due the movement takes place.

The motion sequences are detected by sensing the brightness values of the light, which are in the Change the course of the movement for the individual photodiodes of the diode array of the control device differently. The sequence of movements can be reproduced from the comparison of the currents induced in the individual diodes. In a suitable evaluation the processing and processing of the signals of the individual photodiodes for detecting the movement process, such as the movement of a hand from top to bottom or a foot in the direction of the sensor done. By means of a decision logic, the generation of an output signal determined for the detected motion sequence takes place.

The use of photodiodes enables motion detection even at low light levels, limited by the noise behavior, and over a wide wavelength range.

The resolution of the solid angle of the incident light and its intensity change takes place via a line or net-like arrangement of a plurality of photodiodes. Such an arrangement may e.g. by suitable distances between the photodiodes or the formation of a curved incident surface of the entirety of the photodiodes. Alternatively or additionally, the photodiodes may be associated with a corresponding arrangement of optical components, e.g. a superior lens system and a surface structuring of the photodiodes. In the latter case, the said optical components are integrated in the photodiode array.

By means of these or supplementary optical components also adaptations to certain measuring conditions are possible, such as e.g. a filtering or a selection of defined light incidence angles or preferred directions.

Furthermore, the detection of a movement sequence allows the change of the intensity of the incident light also the local separation between the control device and the interstitial space. It is only an optical coupling on transparent partitions necessary. Consequently, these movements can be carried out either by a person or by a device, whether in a separate, optically connected room or not, in the latter case, for example, to control or initialize automated processes.

The described motion block is in contrast to the distance measurement block serving as a passive detector, so that in contrast to the recording of motion sequences by means of a camera according to the prior art significantly lower quiescent currents can be achieved. However, if the ambient brightness is too low, according to a further embodiment of the method, a minimum value can be set at least during the detection by using an additional light source.

The temporal separation of distance measurement and motion detection makes it possible to activate only the particular one used for further energy reduction of the individual function blocks. In addition, the photodiodes of the control device can be switched as solar cells and used for the period of sleep, in which they are not used for the control method, the energy production.

To carry out the control method, a control device is specified, which has the following basic, structural components. The control device comprises a light transmitter for emitting light into the interstitial space. The light emitter is for the distance block according to above Description of the procedure indispensable component, for the motion block, however, only optional hinzuschaltbar. Accordingly, the light transmitter is operable both in pulsed operation and continuously. Alternatively, for the above-described divergent functions in the distance and motion block or for use in different applications, it is also possible to arrange a plurality of light transmitters, which possibly differ in their wavelength ranges.

The control device further comprises an array of a plurality of photodiodes arranged in at least two rows, e.g. PIN or avalanche diodes as a light receiver for receiving radiation which impinges on this diode arrangement as a result of reflection at an object located in the interstitial space.

Furthermore, a control electronics for controlling the light emitter and the light receiver is arranged so that the light emitter emits pulses of different length and / or intensity and / or timing. By means of the control electronics is also realized that at least some of the light receivers are sequentially either the measuring system for distance measurement, the distance block, or the measuring system for spatially and temporally selecting detection of movement, the motion block, assigned.

The control device also comprises evaluation electronics for evaluating transmitted and / or received radiation, for storing characteristic values of light pulses and distribution characteristics of the photodiode currents, which are selected over the area of the diode array in terms of time or area, and for comparison of detected and stored optical signals and distribution characteristics.

In order to generate the required, optionally variable output signal, a signal generator is also arranged with which an output signal for controlling an external electrical device is to be generated and transmitted to the external electrical device.

As a result of the corresponding control by the control electronics, these components form the two named function blocks which are assigned to the respective system states. Since both function blocks are independent of each other, i. operate without access to the other, both separate structures, but also the use of components of the control device first for one and later for the other function block are possible. In order to allow the adaptation of a control device to different applications, the diode array may comprise more photodiodes than are required for each of the two functional blocks. Such an adaptation can e.g. concern the size or shape of the interstitial space. In such a case, after adaptation, a part of the diode array may be fixedly connected to one and another part fixedly connected to the other function block or to a supplementary function, such as the adaptation of the ambient brightness.

The proposed control device can furthermore be embodied as a compact sensor IC, ie a complex system component in which the essential components such as the light receivers and light transmitters and the control and evaluation electronics and the signal generator are monolithically integrated in one embodiment of the control device, ie arranged on a semiconductor chip are. Thus, the control device is variably deployable to design and a significant reduction in size compared to one of individual components discretely on a Printed circuit board design possible. At present, a reduction to up to one-eighth of the base area can be realized, wherein the electrical contacting takes place via contacts arranged laterally on the housing. With increasing scaling but also depending on the location even smaller dimensions are possible. If, in an optional embodiment, the discrete configuration variant is used, the contacts, for example plugs, are arranged on the sensor side of the printed circuit board, while the components of the control device can be arranged on both sides.

Fig. 1

einen gehäusten Sensorchip als monolithisch integrierte Steuerungsvorrichtung;

Fig. 2

ein Blockschaltbild eines Sensorchips gemäß Fig.1;

Fig. 3

die Lage eines Überwachungsraums in Bezug auf die Lage eines Sensorchips;

Fig. 4A, 4B

ein Programmablaufplan zur Ausführung des erfindungsgemäßen Verfahrens zur Steuerung von externen elektrischen Geräten;

Fig. 5A, 5B

ein Programmablaufplan einer Ausgestaltung des Steuerungsverfahrens gemäß Fig. 4A, 4B

The invention will be explained in more detail with reference to an embodiment. In the accompanying drawing shows in

Fig. 1

a packaged sensor chip as a monolithic integrated control device;

Fig. 2

a block diagram of a sensor chip according to Fig.1 ;

Fig. 3

the location of a monitoring space with respect to the location of a sensor chip;

Fig. 4A, 4B

a program flow chart for carrying out the method according to the invention for the control of external electrical equipment;

Fig. 5A, 5B

a program flowchart of an embodiment of the control method according to Fig. 4A . 4B

The execution of the control method described below is a housed sensor chip 1 according to Fig. 1 based.

The Fig. 1 shows an embodiment of a sensor chip 1 according to the invention in its package 2. Als Package 2 is generally understood to mean the direct encapsulation of a chip, which is often made from a potting compound that meets the electrical and mechanical requirements and whose material is matched to the expected chemical and thermal loads. The package 2 is in the embodiment as QFP sheath (Quas Flat Package - QFP) with a flat rectangular shape, the electrical connections 6, generally referred to as pins, are arranged on the side edges. With such a shape and connection design, the sensor chip 1 can be integrated in various systems by means of a suitable surrounding housing.

The package 2 is opaque, with a transparent cap 4 above the light receiver 8, an arrangement of photodiodes described below, and the light emitter 10. Opaque enclosure 3 and transparent cap 4 have a strength for operating temperatures in the range between -40 ° C and + 105 ° C. The cap 4 is in the embodiment either of Macrolon or Aspec, both materials which have sufficient transmission and is sufficiently temperature resistant for the use of the sensor chip 1 in motor vehicles.

The cap 4 or a special cover for the light emitter 10 and / or the light receiver 8 may be designed as a filter for certain wavelength ranges, which are used for the three-dimensional motion detection, and / or as a diffuser, to a spatial dispersion of the emitted light from the light emitter 10 to achieve and capture with a single ping the entire interception space.

The sensor chip 1 contains as active components a diode array 9 of eight by eight semiconductor photodiodes, which are designed, for example, as avalanche photodiodes.

The amplification effect of the avalanche photodiodes 4 makes it possible to restrict the active area of the diodes used to a very small area. Thus, the space required for the sensor chip 1 can be substantially reduced. The use of avalanche diodes also allows compensation of reflection losses due to the diffuser even with high scattering effect by their gain effect. Alternatively, PIN diodes are also applicable, e.g. if the integration of the sensor chip 1 in the overall system does not require a maximum possible area reduction.

The diode array 9 serves both the distance measurement and the spatially and temporally selecting motion detection by activating or optionally configuring the respectively used photodiodes 4 with the activation of the functional block responsible for the various measurement tasks by the software of the sensor chip 1. The number and arrangement of photodiodes 4 used for a functional block may be the same for each of the applications, but may be different. The light receivers 8 are designed per se or via suitable filters preferably for light in the near infrared range, in the exemplary embodiment in the range of 840 nm to 860 nm. The photodiodes 8 serve both the distance measurement and the spatially and temporally selecting motion detection, according to the respective activation of the function blocks.

The sensor chip 1 further comprises an LED as the light transmitter 10. Alternatively, other light transmitters 10 or more than one are usable, for example, laser diodes or infrared transmitting diodes. For the distance measurement, the LED is pulse-shaped, so that individual as well as rows of pulses with adjustable pulse width and intensity too generate. The wavelengths of the light emitted by the light emitter 10 are in the above-mentioned wavelength range of the light receiver 8 in the visible to near-infrared light, ie in the range between 700 nm and 950 nm.

Furthermore, the sensor chip 1 comprises an application-specific integrated circuit (in Fig. 1 not visible) for signal conditioning, for the evaluation of the received signals and for the generation of evaluable, analogue output signals. Light receiver 8, light emitter 10 and integrated circuit are monolithically integrated.

The block diagram according to Fig. 2 shows the essential components of the sensor chip 1, wherein the separation shown to document only the functional, but not a structural separation of the embodiment.

Functionally, a distinction must be made in the sensor chip 1 between the detector 20 and the integrated circuit 22. The detector 20 comprises the photodiodes 8, of which only three are shown schematically, the light emitter 10 and a signal digitization 24. The latter usually includes a transimpedance converter (not shown) for converting the photocurrent into a low-ohmic measurable voltage and a transimpedance converter following A / D Converter (not shown). Thus, a sufficiently fast measurement with high cutoff frequency and a high linearity in the illumination field of the photodiodes, the functional relationship between the illumination and the diode current can be achieved.

The integrated circuit 22 comprises components of the control electronics, which serves for the signal conditioning for signals to be transmitted, components of the Evaluation electronics for signal processing and signal evaluation for received signals, components of the internal power supply as well as the external communication, to which also a signal generator is to be reckoned, with which an output signal for the control of an external electric device is generated.

The control electronics include a signal conditioning 26, is controlled in conjunction with a timing 28 time and length and / or intensity of a light pulse. In conjunction with a non-volatile memory 30, in which a programming for the process sequence, characteristic signal and measured values, evaluation routines and other data required for the implementation of the control method are stored permanently and configurable, these components are used to control the light emitter or possibly a plurality thereof ,

The evaluation includes a processor 32 for signal evaluation in conjunction with a volatile memory 34 and accesses the purpose of signal evaluation on the timing 28 and the non-volatile memory 30 back.

Both the transmitter, in particular the processor 32, as well as the signal conditioning 26 are externally via an interface 36, which serves the external communication via a corresponding routing within the sensor chip 1 and occupancy of its electrical connections 6 responsive and programmable to the signal transmission and signal evaluation to the particular application of the sensor chip 1 adapt. Via the interface 36 and access to the detector 20 can be realized.

The integrated circuit 22 further comprises an internal power supply 38, in particular the Power supply for the processor 32, for the signal conditioning 26 and the detector 20 is used. This is optionally connected in the opposite direction to the detector 20, whose diode array 9 is connected to capacitors 48 (shown schematically only one). The latter are used for energy storage by charging through the diode array during the idle state of the control device. However, one of the capacitors 48 is also used at the beginning of a control process to determine the ambient brightness as a fundamental optical load as described in more detail below.

In order to provide the external electrical device 46 to be controlled, a consumer-tuned output signal regularly, the integrated circuit 22 as signal generator 40 has a microprocessor, preferably a digital signal processor (DSP). The latter offers the possibility of primarily software adaptation of the output signal to the control of an external electrical device 46.

The sensor chip 1 is connected via a data communication 42, which serves for the input and transmission of data, and via the system supply 44 for the voltage supply of the sensor chip 1 to the overall system, e.g. connected to a vehicle.

The described components of the sensor chip 1 are used according to different stored in non-volatile memory configurations successively different function blocks. Thus, in the course of a control method described in more detail below, a distance measurement by means of pulse measurement method using the light pulse radiating light emitter 10, a selectable arrangement of the embodiment eight times eight photodiodes 8, the signal digitization 24 and the integrated circuit 22. The function block addressed here will be referred to below as a distance block.

After the distance measurement, depending on the design of the control method, a spatially and temporally selected motion detection can take place using a so-called motion block. This functional block comprises a configurable diode arrangement 9 and likewise the signal digitization 24 and the integrated circuit 22, but here with a correspondingly adapted signal evaluation. A light transmitter 10, which was previously used for ranging, is not used in the motion detection.

Optionally, for the case in which the ambient brightness falls below a value which lies in the non-linear region of the illumination field of the photodiodes 8 used, the basic optical load during the detection process is increased by means of a light source 11. The light source 11 may be separately but coupled to the sensor chip 1 or formed on this.

The number and position of the respectively used and accordingly activated photodiodes 8 depend for both functional blocks essentially on the size and the position of the spatial section to be covered. For example, if the entire interception space is 50 ( Fig. 3 ), a larger number of photodiodes 8 may be required than for measurements only in the detection area 54. If the area to be covered is differently extended in different directions, only individual rows of the diode array 9 may be activated. Accordingly, for measurements in the prewarning region 52, other arrangements of activated photodiodes may be used than for measurements in the detection region 54 or in the entire monitoring space 50.

By means of storage, the change of activation can also take place within a control method itself for immediately consecutive measurements or detections.

For the wiring of the detector 20 as a movement block beyond the use of individual photodiodes 8 or a series thereof for the detection of certain movements is possible in order to exclude that they do not unintentionally lead to a control of the external electrical device 46.

Comparable to the freely selectable activation of photodiodes 8 for different applications, one or more light emitters 10 can be arranged, which are controlled jointly or separately, according to their performance parameters, the desired wavelength or the measurement or detection to be performed. In Fig. 2 For the sake of clarity and not limitation, only one light transmitter 10 is shown.

From. Fig. 3 illustrates the situation of the monitoring space 54 in relation to the position of the sensor chip 1 by way of example. The space which directly surrounds the sensor chip 1 is the detection area 54. It is dimensioned so that a motion sequence can be clearly executed, detected and identified therein, to carry out a control with a method described below on the basis thereof. But it must be chosen so small that expected comparable movements that are not to initialize any control, can be excluded. Using the example of the door opening of a vehicle, for example, it must be ensured that passing passers-by do not unintentionally trigger the control.

Adjoining the detection area 54 is the prewarning area 52, which is dimensioned such that there is sufficient time for Is available for verifying events and activating or deactivating various operating states. Both areas 52, 54 together form the monitoring space 50, represented here by the outer line. Depending on the expected events, both areas 52, 54 may also be different from each other or to the sensor chip 1. A partial contact or a complete separation of both areas 52, 54 is possible.

An executable by the control device described above control method is in the program flowchart according to Fig. 4A combined with Fig. 4B The control process is started by starting its main cycle 60. This sets the ranging system from a sleep state to the standby state by activating the function block "removal" of the sensor chip 1 according to its stored configuration. There is no data communication 42 with the entire system required because the entire subsequent process flow is stored in the sensor chip 1. Depending on the configuration of the sensor chip 1, the power supply either takes place completely via the system supply 44 or at least for the first distance measurements via the discharge of capacitors 48 of the sensor chip 1. In one embodiment of the method, the current consumption in the quiescent state is in the range of a few hundred microamps.

If the control method, for example, relate to the opening of a locked vehicle, the main cycle can be configured differently. In the simplest case, the main cycle will be started already with the closing of the vehicle, so that already at this time the readiness of the control device for reopening is established. A more energy efficient Variant can use the detection of the vehicle key equipped with a transponder in the area of the associated transmitter for the start.

A first distance measurement is carried out with the function block "distance", which is referred to below as a distance block, for determining the basic optical load 64. For this purpose, a light pulse, e.g. emitted from a length of about 10 ns. The light pulse serves here only to control the timing of a measuring window, in the course of which a capacitor 48 is charged by the background radiation received by at least one of the photodiodes 8. After expiration of the measurement window, the capacitor charge is interrupted and the optical base load generated by the background radiation is determined from the capacitor voltage. Regardless of the rest of the procedure, the baseline optical load is re-measured at predefined time intervals to account for its change in distance and motion detection.

Thereafter, a first range finding 66 is performed by means of the distance block, which indicates the identification of an event, i. the presence of an object in the interstitial space 50 is used. This is also done by emitting a light pulse, the Identifikationsping, which may for example have a length of 5 to 8 ns, and the reception of reflected radiation by means of the photodiodes 8, if an object is in the interstitial space 50.

About the timing of a measurement window, ie its beginning and end with respect to the transmission of the identification pings in which the photodiodes 8 are active, can be selected whether the object is in the interstitial space 50, in the prewarning 52 or in the detection area 54. Start, length and end of Measuring windows are tuned to the different durations of the reflected pulse for each area. Thus, with an identification ping by definition of different measurement windows for different photodiodes 8 of the diode array 9, the different areas can be monitored. This first measurement serves only to identify an event and is referred to below for better distinction as an identification measurement. If no event is detected with the identification measurement, it is repeated at regular, predefined intervals until the measurement is positive. The time of a positive identification measurement is noted as t ₁ .

Based on the dimensions of the prewarning area 52 and the detection area 54 and the average speed of an expected event, a time difference Δ (t ₂ -t ₁ ) and from this the time t _{2 are} determined 70 at which the event is located with certainty in the detection area 54. This calculation of the time t ₂ is based initially on that a particular event is to trigger the control of the electrical device, for example, a person who approaches a vehicle. This makes it possible to narrow the average speed relatively accurately, either by general default values or by statistically evaluated measurements. For the case mentioned here, the average speed of 1 m / s has been found by tests to be correct.

Furthermore, the calculation is based on the fact that the event at this average speed is certainly still located in the detection area 54, both in the event that it was first identified in the prewarning area 52 and in the case of identification in the detection area 54 above For example, it should be borne in mind that other road users passing by will move at a different speed and will not slow down as a result of the approach.

Similarly, for the various situations to be expected in the respective application, boundary conditions are found which allow verification of a previously identified event as relevant to the high-security control. Of importance, however, is that the event is verified in the detection area 54, since this is defined as a prerequisite for the subsequent control of the external electrical device 46.

The verification is carried out with a further distance measurement comparable to the identification measurement with a light pulse of comparable length, the Verifyingping, but at time t ₂ 72. Here, the location and dimensioning of the measuring window or windows with respect to the Verifyingping be made so that the event beyond doubt in the detection room becomes localized 74. If the verification measurement is negative, ie the event is not located in the detection area 54, which also includes removal of the object from the monitoring space 50, then the preceding identification measurement is rejected at time t ₁ and the loop until the positive identification measurement starts again until the verification measurement is positive.

Only when this is the case, the operating state is started with the actual measurement cycle of the control method 76. This system state differs from the previous state of readiness in that only now the necessary for the control process power supply is applied in full. The system state during the identification and verification measurements, by comparison, it is more likely to be a sleep mode whose power consumption should be limited to such a level that according to one embodiment of the method the power supply alone or at least for the most part is possible from the storage of the diode current, which can be achieved via the diode system 9, which is used as a solar cell when the system is at rest. In one embodiment, the current consumption in the standby state is limited to a maximum of 20 mA.

The further procedure is Fig. 4B shown. During the measurement cycle, a measurement 80, referred to here as a position measurement, is made up of several individual measurements of the pulse measurement method. For this purpose, several light pulses are transmitted by light emitter 10 at regular intervals within a permit period. The permission period is in turn to be dimensioned according to the above considerations for the expected events. In the above example of application this is about 5 ms. Within this time, five light pulses are emitted which advantageously but not necessarily have the same pulse width, eg 5-8 ns, and the same pulse height.

The determination of the position of the event takes place via the measurement and evaluation of the pulse width and / or pulse height of the radiation reflected at the event. By statically secured measurement, simulation or calculation, the expected measured values are to be determined, depending on whether the event is within the detection range 54 or not. To secure the measurement result, the position measurement is evaluated as positive only, ie the event is located in the detection area 54 for the purpose of controlling the external electrical device 46, when of the Single measurements are the majority, in the above example of the five light pulses taking into account the last determined optical base load at least three within one - or more - range 82 predefined pulse width and / or pulse height. If this condition is not fulfilled, ie if the position measurement is negative, it is repeated.

The predefined measured values are stored in the nonvolatile memory 30 of the sensor chip 1 and can be adapted via the data communication 42 to the respective application of the sensor chip 1 integrated in the overall system.

If the position measurement is positive, the distance block is deactivated 84. Only then does the actual control of the external electrical device 46 begins. In the embodiment according to FIG Fig. 4B Now, the generation of an evaluable, analog output signal 86 by means of a suitable signal generator and the transmission of the output signal to the external electrical device 46. Thus, either the control process can be ended 88, which would be the case, for example, when opening a vehicle door, or the process remains in the main cycle and starts again in the standby state with the activation of the distance block and an identification measurement. The latter is the case when repeating or other control methods are to be performed using the same sensor chip 1. If this is not the case, the main cycle is terminated 90, whereby the sensor chip 1 is set to its idle state.

An embodiment of the method described above is intended, by way of example, on the control for opening a vehicle door Fig. 5A combined with Fig. 5B be described, wherein Fig. 5B the continuation of the in Fig. 5A described and not completed process shows. In comparable Way, this method is also applicable to the control of other electrical equipment in other than the vehicle assistance systems.

First, the first process steps until deactivation of the removal block 84 occur as above Fig. 4A . Fig. 4B describe. In that regard, reference is made to the above explanations and agree the names of the individual process steps in the Fig. 4A . Fig. 4B and Fig. 5A . Fig. 5B match.

The control method according to Fig. 5A and Fig. 5B is essentially different from the one in Fig. 4A . Fig. 4B in that at least one further detection is a prerequisite for the signal generation so as to provide different options for signal generation. This can be, for example, a further selection of the verified and position-determined events or the possibility of linking the type of output signal with the additional detection.

For this purpose, after the positively completed position measurement of the function block "distance" as to Fig. 4B In this way, the power consumption of the sensor chip 1 can be further reduced and the components of the sensor chip 1 previously used for the distance block can now be configured and used for the next function.

By activating the next detection block 92, which serves in the embodiment described below, the spatially and temporally resolved motion detection and therefore called motion block, the configuration of the sensor chip 1, ie the activation and linking of the individual components of the sensor chip first according to the new task. The configuration of the motion block is stored in the non-volatile memory 30 of the sensor chip 1 as well as the configuration of the distance block.

The motion detection is performed in contrast to the distance measurement on the basis of the determination of the change of the brightness values due to the event moving in the detection space 54, i. the detection is basically passive and is significantly more influenced by the ambient brightness.

In order to be able to use the linear region of the illumination field of the photodiodes 8 of the sensor chip 1 even for low ambient brightness, the optical base load determined at the beginning of the method is first of all compared with a stored minimum value 94, which is essentially determined by the diode characteristic and the evaluation electronics. If the basic optical load is below a predefined value, the basic optical load is raised to the minimum value or above by means of a light source 11. This takes place either permanently or at least during the time in which the motion detection takes place by means of a motion block. The light source 11 can be coupled to the sensor chip 1 or formed on this, whereby a direct coupling to the detection process is possible, both in terms of time and in terms of intensity. The use of an infrared LED has proven to be advantageous for this case, also due to the low power consumption.

If the optical base load is above this predefined value due to the additional light source 11 or due to the sufficient ambient brightness, the location and time selected motion detection can take place 98.

The motion sequence can be detected either as a distribution characteristic of the photodiode currents, which is determined by the spatially different brightness values as a function of the position of the event relative to the diode array 9 and thus in the detection space at the end of the movement. To a certain extent, this characteristic represents a fingerprint for the detected sequence of movements, since different processes lead at the end to clearly distinguishable positions of the event relative to the sensor chip 1. Alternatively, the temporal resolution can be used by means of the diode array 9, provided that such photodiodes 8 are used whose sensitivity and speed is so high that any movement is temporally resolvable in spatially different diode currents. For this purpose, e.g. Avalanche photodiodes usable.

A thus detected spatially and temporally resolved motion sequence is subsequently compared 100 by means of the evaluation with motion sequences that are stored in the non-volatile memory 30 of the sensor chip 1 as those processes that are relevant to the further control method. These are on the one hand, these processes that are to trigger the control of the external electrical device, in the above example, a vehicle system kick with the foot when approaching a vehicle tailgate or a wave with one hand in front of a vehicle door to the opening.

On the other hand, there are also sequences of movements that occur frequently and for which it must be ensured that they can not lead to a malfunction by chance. This can be, for example, in the monitoring room lingering or slowly moving passers-by, movements of growth on the roadside or Be movements in a car wash. These excluded movements can be selected as described on the basis of the software comparison 100 alone by the transmitter or alternatively be performed in parallel and real with a part of the diode array 9, which is not used for the primary, the device control. For this purpose, the diode array 9 is to control accordingly by means of the control electronics.

For this embodiment of the method of the above-described diode array 9 with eight times eight photodiodes 8, for example, two vertical rows for the primary motion detection and a horizontal row for the latter exclusion detection can be used. Of the remaining photodiodes 8, one or more e.g. for the determination of the basic optical load also during the detection of the motion sequences usable. Alternatively, the entire diode array 9 and can be used successively for the various tasks. These divisions are intended to be indicative only of the many possibilities, but not to be construed restrictive.

If the comparison of the locally and temporally detected motion sequence does not correspond to a stored sequence, the motion detection is repeated until the comparison is positive. Only then is the output signal required for the control of the external electrical device 46 generated in the signal generator of the sensor chip 1 86 and transmitted via the data communication 42 as described above to the external electrical device 46.

As above Fig. 4A . Fig. 4B described now is the option to end the main cycle 90 or go through again. For these options, reference is made to the above explanations.

With the control method according to Fig. 5A and Fig. 5B it is possible to keep the power consumption below the value of 0.5 W throughout the entire process over a temperature range of -40 ° C to 85 ° C. The control device itself described above withstands the genanten temperature range during operation, in storage, this range is still exceeded.

Claims (15)

1. Method for controlling electrical devices (46) by means of three-dimensional motion detection of objects in a monitoring space (50), which is subdivided into a detection region (54) and an adjoining advance warning region (52), by means of a detection system comprising a distance measurement system and a control system, comprising the following method steps of:

   - starting the main cycle of the control method (60) by changing the control apparatus from a quiescent state to a standby state if the presence of an event, referred to as an event below, is expected, only individual measurements being carried out in the standby state,

   - carrying out a distance measurement (66) to the event by means of the control apparatus in the standby state at the time t₁ in order to identify the expected event as being inside the advance warning region (52) or inside the detection region;

   - carrying out a further distance measurement (72) by means of the control apparatus in the standby state in order to verify an event determined using said identification measurement as being in the detection region (54) at a time t₂;

   - the distance measurements (66, 72) being out by means of pulsed light, and only one light pulse, referred to as the identification ping or verification ping below, respectively being used for the identification measurement and/or the verification measurement,

   - starting the measurement cycle (76) of the control method by changing the control apparatus to an operating state if an event determined using said verification measurement is in the detection region (54),

   - the operating state being characterized by a higher power consumption than in the standby state and the latter in turn being characterized by a higher power consumption than in the quiescent state and the power supply needed for the control method being fully applied only in the operating state,

   - carrying out a measurement cycle in order to determine the position, referred to as a position measurement (80) below, of the event verified as being inside the detection region (54),

   - starting the control of an electrical device (46), if the position measurement satisfies predefined conditions, by generating (86) an output signal which is used to control the electrical device (46), and

   - subsequently ending the main cycle of the control method (90) and changing the control apparatus to its quiescent state.
2. Method for controlling electrical devices (46) according to Claim 1, the time difference Δ(t₂-t₁) until the verification measurement being calculated (70) by determining, as of the time t₁, a likely time t₂ at which an event can be found in the detection region (54) on the basis of its average speed and the length of a possible path inside the monitoring space (50).
3. Method for controlling electrical devices (46) according to one of the preceding claims, the position measurement (80) being carried out by means of a plurality of individual measurements each with a light pulse within a predefined permission period, and the generation of an output signal (86) being started only when a predefined number of the measurement results of the individual measurements is (82) within predefined measured value ranges.
4. Method for controlling electrical devices (46) according to one of the preceding claims, the function block of the control apparatus which is used for the distance measurement (66, 72) and shall be referred to as a distance block being deactivated (84) before the output signal is generated.
5. Method for controlling electrical devices (46) according to one of the above-mentioned claims, the control apparatus having a function block for the locally and temporally selected detection of motion sequences (98) in the detection region (54), referred to as a motion block below, and the control method comprising the following further method steps:

   - locally and temporally selected detection of a motion sequence (98) of the event in the detection region (54),

   - generation of an output signal (86) which is dependent on the previously detected motion sequence.
6. Method for controlling electrical devices (46) according to Claim 5, the locally and temporally selective detection of motion sequences (98) being carried out by sensing the change in the brightness values of an arrangement of photodiodes on account of the motion sequence.
7. Method for controlling electrical devices (46) according to either of Claims 5 and 6, a defined optical basic load being set (96) by means of a light source (11) at least during the detection of motion sequences in the event of an ambient brightness which undershoots a predefined value.
8. Method for controlling electrical devices (46) according to one of Claims 5 to 7, the function block of the control apparatus which is used for the distance measurement (66, 72) and shall be referred to as a distance block being deactivated (84) before the locally and temporally selected detection of motion sequences in the detection region.
9. Method for controlling electrical devices (46) according to one of the above-mentioned claims, the light receivers of the control apparatus being an arrangement of photodiodes (8) and this diode arrangement (9) being used, during a quiescent state of the control apparatus, to store electrical energy which suffices to carry out the control method at least until the measurement cycle (76) is started.
10. Apparatus which is designed to carry out the control method according to one of the preceding claims, the control apparatus comprising the following components:

    - a measurement system for the distance measurement, referred to as a distance block,

    - a measurement system for the locally and temporally selective detection of motion sequences, referred to as a motion block,

    - at least one light transmitter (10) as part of the distance block for emitting light into the monitoring space, the light transmitter (10) being able to be operated in pulsed operation,

    - an arrangement of a plurality of photodiodes (8) arranged in at least two rows as light receivers (8) for receiving radiation which strikes the light receiver (8) on account of reflection at an object in the monitoring space, at least some of the light receivers being able to be assigned either to the distance block or to the motion block in succession,

    - control electronics for controlling the light transmitter (10) and the light receivers (8), with the result that the light transmitter (10) emits pulses of different length and/or intensity and/or clocking, and with the result that at least some of the light receivers (8) are assigned either to the distance block or to the motion block in succession,

    - evaluation electronics for evaluating transmitted and/or received radiation, for storing characteristic values of light pulses and distribution characteristics of the photodiode currents which are selected in terms of time or area over the area of the diode arrangement, and for comparing detected and stored optical signals and distribution characteristics, and

    - a signal generator (40) which can be used to generate an output signal for controlling an external electrical device.
11. Control apparatus according to Claim 10, two light transmitters (10) for emitting light in different wavelength ranges into the monitoring space (50) being arranged, and one of said light transmitters with a part of said diode arrangement (9) being assigned to the distance block, and the other of said light transmitters with a part of said diode arrangement (9) being assigned to the motion block.
12. Control apparatus according to either of Claims 10 and 11, the length and/or the intensity and/or the clocking of the light pulses being able to be calculated and freely set using the control electronics.
13. Control apparatus according to one of Claims 10 to 12, also comprising a light source (11) for setting a defined optical basic load.
14. Control apparatus according to one of Claims 10 to 13, also comprising capacitors (48) which can be charged and discharged again using photocurrent from said diode arrangement (9) for energy storage to such an extent that at least one distance measurement (66, 72) can be carried out.
15. Control apparatus according to one of Claims 10 to 14, the light receivers (8) and the light transmitter(s) (10) and the control electronics, the evaluation electronics and the signal generator (40) being monolithically integrated, that is to say arranged on a semiconductor chip.

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